Classical philosophy and Darwinian biology are far more compatible than is usually assumed. In fact, looking at either from the standpoint of the other can enrich and deepen our appreciation of both. From a Darwinian point of view, the theories of Plato and Aristotle deserve to be taken very seriously. From the classical point of view, Darwinian biology is much less reductionist than its enemies suppose.

Monday, January 21, 2013

Dawkins v. Gould & Plato

While cleaning up my basement
today, I found a book I didn’t remember that I had.It’s Dawkins
v. Gould: Survival of the Fittest, by Kim Sterelny.I have been interested in the Dawkins-Gould
debate for some time.

Dawkins (along with philosopher
Daniel Dennett) are “ultra-Darwinians”.They think that the central question in biology is how organisms are so
well adapted to their environments and they hold that the answer is always
natural selection.Moreover, Dawkins
thinks that the primary unit on which natural selection acts is the genes or,
more correctly, gene lineages.Organisms
are just military vehicles built to carry and maintain their genetic architects,
largely by victories in battle with other lineages.Finally, the larger level of evolution‑the emergence
of distinct species‑is just the aggregate of events at the level of organisms
and genes.

Reading a portion of Sterelny’s
book tonight, I think I finally have a grasp of Gould’s counter position.Gould thinks that the basic question is why
there are really a rather small number of basic organism forms and why there is
so much stability in organic form over time.The basic division of the animal kingdom is into phyla, of which there are about thirty.Gould thought that they all appeared at about
the same time and observes that there has been little change in the arrangement
since.While adaptation surely continues,
the era of phyla innovation seems to be well over.

Gould interprets this as
pointing to species selection as one
of the primary force in evolutionary history.From time to time, usually or always as a result of some big change in
the environment (think comet strike), a lot of the biological landscape is
scraped clean and there are openings for new types of organism.There are only so many basic possibilities in
biological design space and only some are suited to the new environment.These are the ones that appear.In this account, it is the species that is
the target of selection and limits on species design that account for the basic
organic models.Chance plays a very big
role in this, as it is chance that steers the comet or whatever else roles the
dice.

By contrast, natural selection
plays a minor role.Individuals in a
successful line will tend to be, well, successful.Once the successful models have been
established, there will be relatively little change until the next apocalypse.

I discussed the difference
between chance, unintentional biasing, and intentional biasing in
a previous post with the regard to explaining the origin of life. While unintentional biasing looks dubious as a
solution to the origin problem, it strikes me that Gould took it very seriously
as an explanation of the basic disparity of life, i.e. explaining why organisms
fall into a number of basic patterns.

Consider the beetle.There are hundreds of thousands, if not
millions, of distinct species of beetle.All of them (by definition) follow the same pattern.A second set of wings evolved into a
retractable coat of armor protecting the functional wings.In the organic form of the species from which
all beetles descend, there was unintentional biasing towards the beetle
form.The proto-beetle, apparently
having two sets of wings and whatnot was unintentionally biased toward a new
and very successful area in design space.

I confess that this strikes me
as a quarrel that does not force me to take sides.I suspect that Gould was right to insist on
the importance of general forms and stability in evolution.I have often thought that the chief thing
that Darwin explained was not how species come to be but why so many of them
remain so stable over time.I like the
emphasis on species selection because it looks to me like a modern version of
Plato and I have the hots for Plato.

At the same time, Gould’s
successful species types are successful because the individual members are well
adapted to their environments.Even if
cumulative instances of selection are less important in the explanation of
general species forms than the ultra-Darwinians suppose, every species is just
a bunch of critters and each critter has to make a living and leave a
legacy.The emphasis on natural
selection and adaptation is still the fundamental explanation of how organisms
are adapted to their environment and how a general species is kept in
business.